极薄带钢搭接焊热影响区断带问题分析与改善

针对某连续退火机组0.2 mm及以下极薄规格带钢出现的焊缝热影响区断带问题,结合实物断口形貌分析,从焊缝增厚量、焊接接头金相组织及熔合情况、焊接接头显微硬度分布等不同角度展开研究,确认断带由过渡区域存在未熔合缺陷、焊缝增厚量大、焊接接头硬度分布不均共同导致。通过合理优化工艺参数,加强对焊轮、碾压轮、刷轮等关键部件的精度及状态的管理,有效解决了极薄规格带钢焊缝热影响区断带问题,提高了机组的作业效率。

Analysis and improvement for strip breakage in HAZ of lap welding of ultra thin strip steel

In order to solve the problem that the weld heat affected zone (HAZ) fracture appeared at 0.2 mm and below ultra thin strip in a continuous annealing line, the research was analyzed by physical fracture morphology, and carried out from different angles, such as weld thickness, metallographic structure and fusion of welded joint, as well as the microhardness distribution of welded joint. It was confirmed that strip breakage was caused by non fusion defects in the transition area, large weld thickness and uneven distribution of hardness for welded joint. By optimizing the process parameters reasonably and strengthening the precision and state management of key components such as welding wheel, rolling wheel and brush wheel, the strip breaking problem in the heat affected zone of the welding seam for ultra thin gauge strip steel was solved effectively, and the operation efficiency of the unit was also improved.